Interconnection assemblies and methods for forming the interconnection assemblies in a battery module

ABSTRACT

Interconnection assemblies and methods are provided. An interconnection assembly includes a first cell tab constructed of a first metal, and a second cell tab disposed against the first cell tab. The second cell tab is constructed of a second metal having a hardness greater than the first metal. The assembly further includes an interconnect member disposed against the second cell tab. The assembly further includes a weld assisting layer disposed against the first cell tab such that the first and second cell tabs are disposed between the weld assisting layer and the interconnect member.

BACKGROUND

Battery modules have utilized interconnect members to electricallycouple battery terminals together. However, when an interconnect memberis being ultrasonically welded to a battery terminal constructed of arelatively soft metal such as aluminum, an ultrasonic welding horn maymove completely through the battery terminal when attempting to weld theterminal to the interconnect member.

The inventor herein has recognized a need for an improvedinterconnection assembly that minimizes and/or eliminates theabove-mentioned deficiency.

SUMMARY

An interconnection assembly in accordance with the exemplary embodimentis provided. The interconnection assembly includes a first cell tab of afirst battery cell. The first cell tab is constructed of a first metal.The interconnection assembly further includes a second cell tab of asecond battery cell. The second cell tab is disposed against the firstcell tab. The second cell tab is constructed of a second metal. Thesecond metal has a hardness greater than a hardness of the first metal.The interconnection assembly further includes an interconnect memberdisposed against the second cell tab. The interconnection assemblyfurther includes a weld assisting layer disposed against the first celltab such that the first and second cell tabs are disposed between theweld assisting layer and the interconnect member. When a welding jointis formed in the first and second cell tabs, the interconnect member,and the weld assisting layer, the weld assisting layer reducesdeformation of the first cell tab.

A method of forming an interconnection assembly in a battery module inaccordance with another exemplary embodiment is provided. The methodincludes providing a first cell tab of a first battery cell, a secondcell tab of a second battery cell, an interconnect member, and a weldassisting layer. The first cell tab is constructed of a first metal, thesecond cell tab is constructed of a second metal. The second metal has ahardness greater than a hardness of the first metal. The method furtherincludes disposing the second cell tab against the first cell tab. Themethod further includes disposing the interconnect member against thesecond cell tab. The method further includes disposing the weldassisting layer against the first cell tab such that the first andsecond cell tabs are disposed between the weld assisting layer and theinterconnect member. The method further includes ultrasonically weldingtogether the first and second cell tabs, the interconnect member, andthe weld assisting layer utilizing an ultrasonic welding machine.

An interconnection assembly in accordance with another exemplaryembodiment is provided. The interconnection assembly includes a firstcell tab of a first battery cell. The first cell tab is constructed of afirst metal. The interconnection assembly further includes a second celltab of a second battery cell disposed against the first cell tab. Thesecond cell tab is constructed of a second metal. The second metal has ahardness greater than a hardness of the first metal. The interconnectionassembly further includes an interconnect member having a U-shapedportion and an extension portion coupled to an end of the U-shapedportion. At least a portion of the first cell tab and at least a portionof the second cell tab are disposed within an open region defined by theU-shaped portion and contacting the U-shaped portion. When a weldingjoint is formed in the first and second cell tabs, the interconnectmember, and the U-shaped portion, the U-shaped portion reducesdeformation of the first cell tab.

A method of forming an interconnection assembly in a battery module inaccordance with another exemplary embodiment is provided. The methodincludes providing a first cell tab of a first battery cell, a secondcell tab of a second battery cell, an interconnect member having aU-shaped portion and an extension portion coupled to a first end of theU-shaped portion. The first cell tab is constructed of a first metal,and the second cell tab is constructed of a second metal. The secondmetal has a hardness greater than a hardness of the first metal. Themethod further includes disposing at least a first portion of the firstcell tab and at least a second portion of the second cell tab within anopen region defined by the U-shaped portion of the interconnect membersuch that the first and second portions contact the U-shaped portion.The method further includes ultrasonically welding together the firstand second cell tabs and the U-shaped portion of the interconnectmember, utilizing an ultrasonic welding machine.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a battery module and an ultrasonic weldingmachine;

FIG. 2 is an enlarged side view of an interconnection assembly utilizedwithin the battery module of FIG. 1 in accordance with an exemplaryembodiment;

FIG. 3 is a schematic of an interconnect member utilized in theinterconnection assembly of FIG. 2;

FIG. 4 is a rear view of the interconnect member of FIG. 3;

FIG. 5 is a front view of the interconnect member of FIG. 3;

FIG. 6 is a flowchart of a method for forming the interconnectionassembly of FIG. 2 in accordance with another exemplary embodiment;

FIG. 7 is a side view of another battery module having otherinterconnection assemblies and an ultrasonic welding machine;

FIG. 8 is an enlarged side view of a weld assisting layer utilizedwithin the battery module of FIG. 7 in accordance with another exemplaryembodiment; and

FIG. 9 is a flowchart of a method for forming an interconnectionassembly utilizing the weld assisting layer of FIG. 8 in accordance withanother exemplary embodiment.

DETAILED DESCRIPTION

Referring to FIG. 1, a battery module 10 in accordance with an exemplaryembodiment, and an ultrasonic welding machine 20 are illustrated. Anadvantage of the battery module 10 is that the module 10 utilizesimproved interconnection assemblies as will be discussed in greaterdetail below. The battery module 10 includes battery cells 28, 30, 32,34, 36, 38, a circuit board 60, and interconnect members 74, 76, 78. Theterm “metal” used herein means either a pure metal or a metal alloy.

The battery cells 28-38 have an identical structure. Each of the batterycells 28-38 have a pouch-type body (not shown) and a pair of cell tabsextending from the pouch type body. For example, the battery cell 32 hasa pouch-type body and a cell tab 102 and another cell tab (not shown)extending therefrom. In one exemplary embodiment, the cell tab 102 isconstructed of aluminum. Further, for example, the battery cell 34 has apouch-type body and a cell tab 104 and another cell tab (not shown)extending therefrom. In one exemplary embodiment, the cell tab 104 isconstructed of copper that has a hardness greater than a hardness ofaluminum.

The circuit board 60 is disposed over the battery cells 28-38 and hasapertures 107, 108, 109 extending therethrough for receiving cell tabsfrom the battery cells therethrough.

Referring to FIGS. 1-5, the interconnect members 74, 76, 78 are providedto be electrically coupled to cell tabs of the battery cells 28-38. Thestructure of the interconnect members 74-78 are identical to oneanother. In one exemplary embodiment, the interconnect members 74-78 areconstructed of copper. Of course, in an alternative embodiment, theinterconnect member 74-78 could be constructed of other metals harderthan aluminum such as nickel alloys or stainless steel for example. Forpurposes of simplicity, the interconnect member 76 will be described ingreater detail below. The interconnect member 76 includes a U-shapedportion 120, an extension portion 122, and coupling tabs 124, 126, 128,130.

The U-shaped portion 120 defines an open region 121 for receiving thecell tabs 102, 104 therein. The U-shaped portion includes walls 140, 142that are substantially parallel to one another, and an arcuate-shapedportion 144 coupled between the walls 140, 142. In one exemplaryembodiment, a thickness of the walls 140, 142 are substantiallyidentical to one another. In an alternative embodiment, the wall 140 hasa thickness less than the thickness of the wall 142 to allow for animproved weld joint to be formed in the interconnection assembly 149.

The extension portion 122 extends from the wall 140 and is provided todirect the cell tabs 102, 104 into the open region 121 defined by theU-shaped portion 120.

The coupling tabs 124, 126, 128, 130 extend from the wall 142 of theU-shaped portion 120 and are configured to be received in respectiveapertures within the circuit board 60 for coupling the interconnectmember 76 to the circuit board 60.

When the interconnect member 76 is welded to the cell tabs 102, 104 bythe ultrasonic welding machine 20, the interconnect member 76 and thecell tabs 102, 104 comprise an interconnection assembly 149. Anadvantage of the interconnection assembly 149 is that the assembly mayutilize the wall 140 constructed of copper or another metal (e.g.,nickel alloys or stainless steel) harder than aluminum to protect thealuminum cell tab 102 during ultrasonic welding such that an ultrasonicwelding horn 160 does not penetrate through the aluminum cell tab 102before forming a weld joint within the wall 140, the cell tabs 102, 104,and the wall 142.

Referring to FIG. 1, the ultrasonic welding machine 20 includes theultrasonic welding horn 160 and the anvil 162. During ultrasonic weldingof the interconnect member 76 to the cell tabs 102, 104, the ultrasonicwelding horn 160 contacts the wall 140 of the interconnect member 76,and the anvil 162 contacts the wall 142 of the interconnect member 76.

Referring to FIG. 6, a flowchart of a method for forming theinterconnection assembly 149 in accordance with another exemplaryembodiment will be explained.

At step 180, a user provides the cell tab 102 of the battery cell 132,the cell tab 104 of the battery cell 34, and the interconnect member 76.The interconnect member 76 has the U-shaped portion 120 and an extensionportion 122 coupled to a first end of the U-shaped portion 120. The celltab 102 is constructed of a first metal (e.g., aluminum), and the celltab 104 is constructed of a second metal (e.g., copper). The secondmetal has a hardness greater than a hardness of the first metal.

At step 182, the user disposes at least a first portion of the cell tab102 and at least a second portion of cell tab 104 within the open region121 defined by the U-shaped portion 120 of the interconnect member 76such that the first and second portions contact the U-shaped portion120.

At step 184, the ultrasonic welding machine 20 ultrasonically weldstogether the cell tabs 102, 104 and the U-shaped portion 120 of theinterconnect member 76.

Referring to FIGS. 7 and 8, a battery module 200 in accordance withanother exemplary embodiment, and an ultrasonic welding machine 20 areillustrated. An advantage of the battery module 200 is that the module200 utilizes improved interconnection assemblies as will be discussed ingreater detail below. The battery module 10 includes battery cells 210,212, 214, 216, 218, 220, a circuit board 230, interconnect members 240,242, 244, and weld assisting layers 250, 252, 254.

The battery cells 210-220 have an identical structure. Each of thebattery cells 210-220 have a pouch-type body (not shown) and a pair ofcell tabs extending from the pouch type body. For example, the batterycell 214 has a pouch-type body (not shown) and a cell tab 274 andanother cell tab (not shown) extending therefrom. In one exemplaryembodiment, the cell tab 274 is constructed of aluminum. Further, forexample, the battery cell 216 has a pouch-type body (not shown) and acell tab 276 and another cell tab (not shown) extending therefrom. Inone exemplary embodiment, the cell tab 276 is constructed of copper thathas a hardness greater than a hardness of aluminum.

The circuit board 230 is disposed over the battery cells 210-220 and hasapertures 231, 232, 234 extending therethrough for receiving cell tabsfrom the battery cells therethrough.

The interconnect members 240, 242, 244 are provided to be electricallycoupled to cell tabs of the battery cells 210-220. The structure of theinterconnect members 240-244 are identical to one another. In oneexemplary embodiment, the interconnect members 240-244 are constructedof copper. Of course, in an alternative embodiment, the interconnectmembers 240-244 could be constructed of other metals (e.g., nickelalloys or stainless steel) that are harder than aluminum. For purposesof simplicity, the interconnect member 242 will be described in greaterdetail below. The interconnect member 242 includes walls 290, 292, and acoupling tab 294 and other coupling tabs (not shown). The wall 292extends from an end of the wall 290 and is disposed substantiallyperpendicular to the wall 290. The coupling tab 294 extends from an endof the wall 292 and is disposed substantially perpendicular to the wall292. The coupling tab 294 and the other coupling tabs (not shown) areconfigured to couple the interconnect member 242 to the circuit board230.

The weld assisting layers 250-254 are provided to be disposed adjacentto aluminum cell tabs to prevent the ultrasonic welding horn 160 fromforming holes in the aluminum cell tabs during formation of a weld jointin the weld assisting layer252, the cell tabs 274, 276, and theinterconnect member 242. The weld assisting layer 252 includes a flatwall portion 300 and an arcuate-shaped portion 302 that extends from anend of the flat wall portion 300. The flat wall portion 300 is disposedadjacent to the cell tab 274 and the arcuate-shaped portion extends overtop ends of the cell tabs 274, 276. In one exemplary embodiment, athickness of each of the weld assisting layers 250-254 is substantiallyequal to a thickness of the wall 290 of the interconnect member 242. Inan alternative embodiment, a thickness of each of the weld assistinglayers 250-254 is less than a thickness of the wall 290 of theinterconnect member 242 to allow for an improved weld in theinterconnection assembly 305. The weld assisting layers 250-254 can beconstructed of copper or another metal.

When the weld assisting layer 252 and the interconnect member 242 iswelded to the cell tabs 274, 276 by the ultrasonic welding machine 20,the weld assisting layer 252, the cell tabs 74, 276, and theinterconnect member 242 comprise an interconnection assembly 305. Anadvantage of the interconnection assembly 305 is that the assemblyutilizes the weld assisting layer 252 to protect the aluminum cell tab274 during ultrasonic welding such that the ultrasonic welding horn 160does not penetrate through the aluminum cell tab 274 before forming aweld joint within the weld assisting layer 252, the cell tabs 274, 276,and the interconnect member 242.

Referring to FIG. 9, a flowchart of a method for forming theinterconnection assembly 305 in accordance with another exemplaryembodiment will be explained.

At step 320, a user provides the cell tab 274 of the battery cell 214,the cell tab 276 of the battery cell 216, the interconnect member 242,and the weld assisting layer 252. The cell tab 274 is constructed of afirst metal (e.g., aluminum), the cell tab 276 is constructed of asecond metal (e.g., copper). The second metal has a hardness greaterthan a hardness of the first metal.

At step 322, the user disposes the cell tab 276 against the cell tab274.

At step 324, the user disposes the interconnect member 242 against thecell tab 276.

At step 326, the user disposes the weld assisting layer 252 against thecell tab 274 such that the cell tabs 274, 276 are disposed between theweld assisting layer 252 and the interconnect member 242.

At step 328, the ultrasonic welding machine 20 ultrasonically weldstogether the cell tabs 274, 276, the interconnect member 242, and theweld assisting layer 252.

The interconnection assemblies and the methods of forming theinterconnection assemblies described herein provide a substantialadvantage over other assemblies and methods. In particular, theinterconnection assemblies and methods provide a technical effect ofutilizing either an interconnect member or a weld assisting layer toprevent an ultrasonic welding horn from forming holes in a cell tabconstructed of a relatively soft metal such as aluminum.

While the claimed invention has been described in detail in connectionwith only a limited number of embodiments, it should be readilyunderstood that the invention is not limited to such disclosedembodiments. Rather, the claimed invention can be modified toincorporate any number of variations, alterations, substitutions orequivalent arrangements not heretofore described, but which arecommensurate with the spirit and scope of the invention. Additionally,while various embodiments of the claimed invention have been described,it is to be understood that aspects of the invention may include onlysome of the described embodiments. Accordingly, the claimed invention isnot to be seen as limited by the foregoing description.

We claim:
 1. An interconnection assembly, comprising: a first cell tabof a first battery cell, the first cell tab being constructed of a firstmetal; a second cell tab of a second battery cell, the second cell tabbeing disposed directly on and against the first cell tab, the secondcell tab being constructed of a second metal, the second metal having ahardness greater than a hardness of the first metal; an interconnectmember being disposed directly on and against the second cell tab; and aweld assisting layer being disposed directly on and against the firstcell tab such that the first and second cell tabs are disposed betweenthe weld assisting layer and the interconnect member, such that when awelding joint is formed in the first and second cell tabs, theinterconnect member, and the weld assisting layer, the weld assistinglayer reduces deformation of the first cell tab.
 2. The interconnectionassembly of claim 1, wherein the first metal is aluminum.
 3. Theinterconnection assembly of claim 2, wherein the second metal is copper.4. The interconnection assembly of claim 3, wherein the weld assistinglayer has a flat wall portion and an arcuate-shaped portion extendingfrom the flat wall portion.
 5. The interconnection assembly of claim 4,wherein the flat wall portion being disposed directly on and against thefirst cell tab, and the arcuate-shaped portion extending from an end ofthe flat wall portion past both an end of the first cell tab and an endof the second cell tab to the interconnect member.
 6. Theinterconnection assembly of claim 1, the weld assisting layer isconstructed of either the second metal or a third metal.
 7. Theinterconnection assembly of claim 1, wherein the interconnect member isconstructed of either the second metal or a third metal.
 8. Aninterconnection assembly, comprising: a first cell tab of a firstbattery cell, the first cell tab being constructed of aluminum; a secondcell tab of a second battery cell, the second cell tab being disposeddirectly on and against the first cell tab, the second cell tab beingconstructed of copper; an interconnect member being disposed on andagainst the second cell tab; and a weld assisting layer being disposedon and against the first cell tab such that the first and second celltabs are disposed between the weld assisting layer and the interconnectmember, such that when a welding joint is formed in the first and secondcell tabs, the interconnect member, and the weld assisting layer, theweld assisting layer reduces deformation of the first cell tab.
 9. Theinterconnection assembly of claim 8, wherein the weld assisting layerhas a flat wall portion and an arcuate-shaped portion extending from anend of the flat wall portion.
 10. The interconnection assembly of claim9, wherein the flat wall portion being disposed directly on and againstthe first cell tab, and the arcuate-shaped portion extending from an endof the flat wall portion past both an end of the first cell tab and anend of the second cell tab to the interconnect member.